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        <td class="header">&nbsp; Goldstein Phase Filtering<br>
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<h3>Goldstein Phase Filtering Operator</h3>Phase filtering is a
preprocessing technique that greatly reduces the residues in the later
on&nbsp; phase unwrapping step and enhances the phase unwrapping
accuracy. The method implemented in this operator is a nonlinear
adaptive algorithm proposed by Goldstein and Werner [1] in 1998.<br>
<h4>Input and Output</h4>
<ul>
    <li>The
        input to this operator is the output of Interferogram Formation operator.
    </li>
    <li>The output of this operator is a stack of filtered I/Q bands.</li>
</ul>
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<h4>Parameters Used</h4>&nbsp;&nbsp; The following processing parameter is required for this operator (see Figure
1):<br>
<ul>
    <li>Adaptive Filter Exponent: A value lies in range (0,1]. The larger the value the stronger the filtering.<br>
    </li>
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<img style="width: 450px; height: 450px;" alt="" src="images/goldstein_phase_filtering_ui.jpg"><br>
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&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; Figure 1. Goldstein Phase Filtering operator
UI<br>
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<p> Reference:&nbsp;</p>

<p>[1] R.M. Goldstein and C.L. Werner, "Radar
    Interferogram Phase Filtering for Geophysical Applications,"
    Geophysical Research Letters, 25, 4035-4038, 1998<br>
</p>


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